Both kidneys tested positive for mycobacterium tuberculosis on renal biopsy, including a positive urine culture. The right kidney is known to be non-functional. The patient is also known with a thimble bladder. The patient is HIV-negative.

Renal TB reactivates after a long latency period and is predominantly seen in those over 20 years old ¹.

TB spreads hematogenously to the renal cortex, which is thought to provide an ideal environment for granulomas due to its high oxygen content ². TB mycobacteria flow down the nephrons and get trapped at the narrow loops of Henle, resulting in infection of the renal papillae ³. This causes sloughing due to inflammation ². The renal parenchyma heals by fibrosis and stricture formation ² leading to cortical thinning, parenchymal cavitation, blunted calyces, and caliectasis ^1-3. Strictures of the pelvicalyceal system may progress due to the body’s recovery response despite treatment ³. Note that in this case, no hydronephrosis is seen.

Once the renal granulomas enter the upper collecting tract and pass distally, ureteric and bladder TB are also possible, resulting in a thimble bladder ².

No secondary signs of pyelonephritis could definitively be identified.